Transmission gear synchronizer blocker ring formed of a thermoplastic material

ABSTRACT

A transmission gear synchronizer includes a sliding sleeve a hub and a blocker ring. The sliding sleeve has an inner surface defining a sleeve spline. The hub is received within the sliding sleeve. The hub has a plurality of gear teeth extending radially outward from a root diameter of the hub. The plurality of gear teeth are configured to engage the sleeve spine. A notch is disposed proximate the root diameter of the hub and spaced apart from the plurality of gear teeth. The blocker ring comprises a thermoplastic material. The blocker ring comprises a thermoplastic material. The blocker ring has a plurality of molded clutch teeth extending radially outward from a root diameter of the blocker ring. The plurality of molded clutch teeth are configured to engage the sleeve spline in response to the sliding sleeve engaging the blocker ring during a transmission shift event.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 14/608,994 filed on Jan. 29, 2015, which claims the benefit ofU.S. Provisional Application No. 61/932,966, filed Jan. 29, 2014; thedisclosures of which are hereby incorporated in their entirety byreference herein.

FIELD

The present disclosure relates to a transmission gear synchronizerblocker ring formed of a thermoplastic material.

BACKGROUND

A dual cone synchronizer with servo action is disclosed in U.S. Pat. No.5,135,087

SUMMARY

A transmission gear synchronizer includes a sliding sleeve a hub and ablocker ring. The sliding sleeve has an inner surface defining a sleevespline. The hub is received within the sliding sleeve. The hub has aplurality of gear teeth extending radially outward from a root diameterof the hub. The plurality of gear teeth are configured to engage thesleeve spine. A notch is disposed proximate the root diameter of the huband spaced apart from the plurality of gear teeth. The blocker ringcomprises a thermoplastic material. The blocker ring comprises athermoplastic material. The blocker ring has a plurality of moldedclutch teeth extending radially outward from a root diameter of theblocker ring. An inner surface defines a molded spline. The plurality ofmolded clutch teeth are configured to engage the sleeve spline inresponse to the sliding sleeve engaging the blocker ring during atransmission shift event.

According to other features, the blocker ring has an outer surfacedefining a molded engagement pad extending radially outward from theouter surface of the blocker ring. The molded engagement pad isconfigured to nest within the notch of the hub. The notch is configuredto substantially align the molded clutch teeth relative to the sleevespline and permit relative movement between the blocker ring, the huband the sliding sleeve when the molded engagement pad is nested withinthe notch of the hub. The gear synchronizer further includes anengagement ring having a cone extending from a surface of thetengagement ring towards the hub and gear teeth extending radiallyoutward from the root diameter of the engagement ring. The molded splineof the blocker ring is configured to engage the cone during atransmission shift event. The thermoplastic material comprises ahigh-performance polymer composite.

A transmission gear synchronizer according to other features includes asliding sleeve, a hub and a blocker ring. The sliding sleeve has aninner surface defining a plurality of sleeve teeth extending radiallyinward from the inner surface of the sliding sleeve towards atransmission shaft. The hub has a plurality of hub gear teeth extendingradially outward from a root diameter of the hub. The hub is configuredto be received within the sliding sleeve. The blocker ring is formedfrom a thermoplastic material and disposed adjacent to the hub. Theblocker ring has (i) a plurality of molded clutch teeth extendingradially outward from a root diameter of the blocker ring, and (ii) aninner surface defining a plurality of molded grooves extending axiallyalong the inner surface of the blocker ring, wherein each molded grooveof the plurality of molded grooves is disposed substantially parallel toa longitudinal axis of the blocker ring.

According to other features, each sleeve tooth of the plurality ofsleeve teeth have a tip. The tip is defined by a first surface disposedat a first angle relative to a longigudinal axis of a transmission shaftand a second surface disposed at a second angle relative to thelongitudinal axis of the transmission shaft. Each molded clutch tooth ofthe plurality of molded clutch teeth has an end surface defined by athird surface disposed at a third angle relative to the longitudinalaxis of the transmission shaft and a fourth surface disposed at a fourthangle relative to the longitudinal axis of the transmission shaft. Thesecond surface is configured to engage the third surface during atransmission upshift event. The first surface is configured to engagethe fourth surface of an adjacent molded clutch tooth of the blockerring during a transmission downshift event.

A transmission gear synchronizer constructed in accordance to additionalfeatures includes a sliding sleeve, a hub and a blocker ring. Thesliding sleeve has having an inner surface defining a plurality ofsleeve teeth extending radially inward from the inner surface of thesliding sleeve towards a transmission shaft. Each sleeve tooth of theplurality of sleeve teeth has a tip, the tip defined by a first surfacedisposed at a first angle relative to a longitudinal axis of atransmission shaft and a second surface disposed at a second anglerelative to the longitudinal axis of the transmission shaft. The hub hasa plurality of hub gear teeth extending radially outward from a rootdiameter of the hub, the hub configured to be received within thesliding sleeve. The blocker ring is formed from a thermoplastic materialand disposed adjacne the hub. The blocker ring has a plurality of moldedclutch teeth extending radially outward from a root diameter of theblocker ring. Each molded clutch tooth of the plurality of molded clutchteeth has an end surface defined by a third surface disposed at a thirdangle relative to the longitudinal axis of the transmission shaft and afourth surface disposed at a fourth angle relative to the longitudinalaxis of the transmission shaft. The second surface is configured toengage the third surface during a transmission upshift event and thefirst surface is configured to engage the fourth surface of an adjacentmolded clutch tooth of the blocker ring during a transmission downshiftevent. An inner surface defines a plurality of molded grooves extendingaxially along the inner surface of the blocker ring, each molded grooveof the plurality of molded grooves is disposed substantially parallel toa longitudinal axis of the blocker ring.

According to additional features, the transmission gear synchronizerfurther comprises an engagement ring disposed between a gear and theblocker ring, the engagement ring having a cone extending axially awayfrom a surface of the engagement ring and tapering towards the hub. Theplurality of molded grooves of the blocker ring are configured tofrictionally engage the cone during at least one of the transmissionupshift event and the transmission downshift event. The first surfacehas a first length and the second surface has a second length. Thesecond length is greater than the first length. The third surface has athird length and the fourth surface has a fourth length. The thirdlength is substantially similar to a second length of the secondsurface. Each sleeve tooth of the plurality of sleeve teeth has a firstside surface extending from the inner surface to the first surface and asecond side surface spaced apart from the first side surface. The secondside surface extends from the inner surface to the second surface. Thefirst side surface and the second side surface are progressively fartherapart from one another along the sleeve tooth towards the tip.

In other features, the first surface and the second surface are disposedat an acute angle with respect to each other. The first surface and thesecond surface are disposed at an obtuse angle with respect to eachother. The engagement of the second surface with the third surfacedefines a first contact area and the engagement of the first surfacewith the fourth surface of the adjacent molded clutch tooth of theblocker ring defines a second contact area, the first contact areasubstantially similar to the second contact area. The hub defines anotch and wherein the blocker ring has an outer surface defining amolded engagement pad extending radially outward from the outer surfaceof the blocker ring, the molded engagement pad configured to nest withinthe notch of the hub.

According to other features, the sliding sleeve defines a sleeve spline.The notch is configured to substantially align the molded clutch teethrelative to the sleeve spline and permit relative movement between theblocker ring, the hub and the sliding sleeve. The molded engagement padis nested within the notch of the hub. The thermoplastic materialcomprises a high-performance polymer composite. The thermoplasticmaterial has a tensile strength within a range defined by 200-500 MPa.The blocker ring defines an indexing slot disposed proximate the moldedengagement pad.

Further areas of applicability of the teachings of the presentdisclosure will become apparent from the detailed description, claimsand the drawings provided hereinafter, wherein like reference numeralsrefer to like features throughout the several views of the drawings. Itshould be understood that the detailed description, including disclosedembodiments and drawings referenced therein, are merely exemplary innature intended for purposes of illustration only and are not intendedto limit the scope of the present disclosure, its application or uses.Thus, variations that do not depart from the gist of the presentdisclosure are intended to be within the scope of the presentdisclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a compound manual transmission with thecase partially removed;

FIG. 2 is a perspective view of an exemplary transmission gearsynchronizer with a sliding sleeve assembly in a neutral position;

FIG. 3 is a perspective view of an exemplary transmission gearsynchronizer with a sliding sleeve in a locked position with a gear;

FIG. 4 is an exploded perspective view of an exemplary transmission gearsynchronizer;

FIGS. 5A, 5B, are partial sectional views of a sliding sleeve assemblyin an engaged position with a blocker ring clutch tooth;

FIG. 6 is a partial sectional view of a sliding sleeve assembly in anengaged position with a blocker ring clutch tooth;

FIG. 7 is a perspective view of an exemplary thermoplastic blocker ring;

FIG. 8 is a partial perspective view of an exemplary thermoplasticblocker ring; and

FIG. 9 is a perspective view of an exemplary thermoplastic blocker ring.

DESCRIPTION

Detailed embodiments of the present invention are disclosed herein;however, it is to be understood that the disclosed embodiments aremerely exemplary of the invention that may be embodied in various andalternative forms. The figures are not necessarily to scale; somefeatures may be exaggerated or minimized to show details of particularcomponents. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

Referring to FIG. 1, a transmission 10 may be provided with a vehiclesuch as an automobile, a truck or the like. The transmission 10 may beconfigured as a mechanical manual transmission, a dual clutchtransmission, an automated transmission, a sequential transmission, or amechanical device that may require differential speed equalization. Thetransmission 10 transmits power from a power source, such as an internalcombustion engine to a drive axle.

The transmission 10 may include an input shaft 20 configured to engagethe power source (not shown) via a clutch, a fluid coupling, or aflywheel. The transmission 10 may include an output shaft 22 configuredto engage a differential or drive member (not shown). The combination ofthe input shaft 20 and the output shaft 22 is commonly referred to asthe transmission main shaft. In at least one embodiment, the outputshaft 22 includes a yoke 24 coupled to a differential or a drive member.

The transmission 10 may include a first gear set 30, a second gear set32, and a transmission gear synchronizer 34. The first gear set 30, thesecond gear set 32, and the transmission gear synchronizer 34 eachrotatably disposed within a transmission housing 36.

The first gear set 30 may include a first plurality of gears 40 disposedconcentrically about a first transmission shaft 42 such that the firstgear set 30 is supported by the first transmission shaft 42. The firstgear set 30 may be journaled on the first transmission shaft 42. In atleast one embodiment, the first plurality of gears 40 may include afirst gear 44 spaced apart from a second gear 46. The first gear 44 andthe second gear 46 may be disposed substantially perpendicular to alongitudinal axis 48 of the first transmission shaft 42. The second gearset 32 may include a second plurality of gears 50 disposedconcentrically about a second transmission shaft 36 such that the secondgear set 32 is supported by the second transmission shaft 36. The secondtransmission shaft 36 may commonly be referred to as a countershaft.

The first transmission shaft 42 may be spaced apart from and disposedsubstantially parallel to the second transmission shaft 36. In at leastone embodiment, the second plurality of gears 50 may include a thirdgear 54 spaced apart from a fourth gear 56. The third gear 54 and thefourth gear 56 may be disposed substantially perpendicular to alongitudinal axis 58 of the second transmission shaft 52. The secondgear set 32 may be journaled on the second transmission shaft 36.

The first gear set 30 may be rotatably aligned with the second gear set32. The first plurality of gears 40 of the first gear set 30 engage acorresponding gear of the second plurality gears 50 of the second gearset 32 such that the second gear set 32 are in meshed engagement withthe first gear set 30. In at least one embodiment, the first gear 44 mayremain in constant mesh or engagement with the third gear 54 and/or thesecond gear 46 may remain in constant mesh or engagement with the fourthgear 56.

The first plurality of gears 40 and the second plurality of gears 50 maybe configured to transmit torque from the input shaft 20 to the outputshaft 22. The first plurality of gears 40 and the second plurality gears50 are configured to provide multiple forward and/or reverse gear ratiosor torque ratios. An operator of a vehicle incorporating thetransmission 10 may selectively engage at least one of the gears of thefirst plurality of gears 40 of the first gear set 30 and/or at least oneof the gears of the second plurality of gears 50 of the second gear set32. The selective engagement of the gears defines a plurality of torqueflow paths through the first gear set 30 and the second gear set 32 tovary an output torque or gear ratio of the transmission 10.

The shift lever 60 may be operatively connected to at least one shiftfork 62 by a set of linkages (not shown). The shift fork 62 translates asliding gear selector, collar, or sliding sleeve 70 between gears of thefirst plurality of gears 40 and/or gears of the second plurality ofgears 50. A sliding sleeve 70 may be rotatably disposed about the firstand/or second transmission shaft 42, 52.

The sliding sleeve 70 may translate towards a desired gear responsive tomovement of the shift fork 62. The sliding sleeve 70 may be configuredto lock onto a freely spinning gear or engagement ring associated withthe desired gear to lock the freely spinning gear associated with thedesired gear to the transmission shaft such that the transmission shaft42, 52 spins together with the desired gear. The engagement of thesliding sleeve 70 with the desired gear may result in nibble, notch, orother transmission effects that may negatively affect transmission shiftquality if the rotational speed of collar is not substantially similarto the rotational speed of the desired gear. The transmission gearsynchronizer 34 may be provided to brake or accelerate the slidingsleeve 70 and/or the desired gear such that the rotational speed of thesliding sleeve 70 and the desired gear are substantially similar todampen or minimize the effects of notch, nibble, or other undesiredtransmission shift effects. In at least one embodiment, the transmissiongear synchronizer 34 may adjust the rotational speed of at least one ofthe first transmission shaft 42 and the second transmission shaft 52 andthe desired gear.

Referring to FIG. 2, the transmission gear synchronizer 34 is shown withthe sliding sleeve 70 in a neutral position between the first gear 44and the second gear 46. Referring to FIG. 3, the transmission gearsynchronizer 34 is shown with the sliding sleeve 70 translated towardsthe desired gear (e.g. the first gear 44) responsive to actuation by theshift fork 62.

The transmission gear synchronizer 34 may be disposed concentricallyabout the first transmission shaft 42 such that the transmission gearsynchronizer 34 is supported by the first transmission shaft 42. Thetransmission gear synchronizer 34 may be disposed between or adjacent tothe first gear 44 and the second gear 46 of the first plurality of gears40 of the first gear set 30. In at least one embodiment, thetransmission gear synchronizer 34 may be disposed concentrically aboutthe second transmission shaft 52 such that the transmission gearsynchronizer 34 is supported by the second transmission shaft 52. Thetransmission gear synchronizer 34 may be disposed between or adjacent tothe third gear 54 and the fourth gear 56 of the second plurality ofgears 50 of the second gear set 32.

Referring to FIG. 4, an exploded perspective view of an exemplarytransmission gear synchronizer 34 is shown. The transmission gearsynchronizer 34 may be a triple cone transmission gear synchronizerhowever other transmission gear synchronizer configurations arecontemplated such as a single cone, dual cone, or other multi-conetransmission gear synchronizers. The transmission gear synchronizer 34may include a sliding sleeve 70, a fixed hub 72, a synchronization ringor blocker ring 74, an inner synchronizer ring assembly 76, and anengagement ring 78. In at least one embodiment, the transmission gearsynchronizer 34 may be a single cone transmission gear synchronizerhaving the inner synchronization ring assembly 76 excluded. In at leastone embodiment, the transmission gear synchronizer 34 may be a dual conetransmission gear synchronizer having at least one of an intermediatesynchronization ring 80 or the inner synchronization ring 82 excluded.

Irrespective of the transmission gear synchronizer 34 configuration, thetransmission gear synchronization process follows similar steps during atransmission shift event. The transmission shift event may be atransmission upshift event when a transmission gear ratio moves from alower gear ratio to a higher gear ratio, e.g. N-1, 1-2, 2-3, 3-4, etc.The transmission shift event may be a transmission downshift event whenthe transmission gear ratio moves from a higher gear ratio to a lowergear ratio, e.g. 4-3, 3-2, 2-1, 1-N, etc. During a transmission shiftevent, the sliding sleeve 70 is moved by the shift fork 62 towards thedesired gear to be engaged. Responsive to a rotational speed differencebetween the desired gear and the combination of the sliding sleeve 70and the fixed hub 72, which may be referred to as a sliding sleeveassembly 84, the sliding sleeve 70 is prevented from engaging theengagement ring 78 by the blocker ring 74.

The blocker ring 74 is configured to frictionally engage a cone of theengagement ring 78, the intermediate synchronization ring 80, or theinner synchronization ring 82 associated with the desired gear. Thefrictional engagement generates a frictional torque to brake oraccelerate the rotational speed of the sliding sleeve assembly 84 and/orthe engagement ring 78, such that the rotational speeds of the slidingsleeve assembly 84 and the engagement ring 78 or the desired gear aresynchronized. Responsive to the synchronization of the rotationalspeeds, the sliding sleeve 70 may be further translated to engage theengagement ring 78 to complete the transmission shift event.

The sliding sleeve 70 may be configured as a generally cylindrical bodydisposed concentrically about an axis of the first transmission shaft42. The sliding sleeve 70 may have an outer surface 90 and an innersurface 92. The outer surface 90 may define an engagement groove 94 thatmay receive at least a portion of the shift fork 62. The movement of theshift fork 62 within the engagement groove 94 may translate the slidingsleeve 70 away from the neutral position or from a current gear towardsthe desired gear.

The sliding sleeve 70 may be configured as an internal gear having asleeve spline disposed about the inner surface 92. The sleeve spline maybe configured as a plurality of sleeve teeth 96 that extend radiallyinward from the inner surface 92 of the sliding sleeve 70 towards thefirst transmission shaft 42.

Each sleeve tooth 100 of the plurality of sleeve teeth 96 has a tip 102.The tip 102 may be angled with respect to the longitudinal axis 48 ofthe first transmission shaft 42. The tip 102 may be defined by a firstsurface 104 and a second surface 106. The first surface 104 may bedisposed at a first angle relative to the longitudinal axis 48 of thefirst transmission shaft 42. The second surface 106 may be disposed at asecond angle relative to the longitudinal axis 48 of the firsttransmission shaft 42. The first surface 104 and the second surface 106may define an angle .theta.

Referring to FIGS. 5A, 5B, and 6, a partial sectional view of a sleevetooth 100 of the sliding sleeve 70 in an engaged position with theblocker ring 74. In at least one embodiment, the first surface 104 andthe second surface 104 may be disposed at an obtuse angle .theta..sub.Owith respect to each other. Referring to FIG. 6, in at least oneembodiment, the first surface 104 and the second surface 106 may bedisposed at an acute angle, .theta..sub.A, with respect to each other.

The first surface 104 may have a first length, I.sub.1. The secondsurface 106 may have a second length, I.sub.2. As shown in FIGS. 5A and5B, the second length, I.sub.2, may be greater than the first length,I.sub.1, such that the first surface 104 and the second surface 106 areasymmetric. As shown in FIG. 6, the first length, I.sub.1, and thesecond length, I.sub.2, may be substantially similar to each other, suchthat the first surface 104 and the second surface 106 are symmetric.

The sleeve tooth 100 may have a body portion 110. The body portion 110may have a first side surface 112 extending from the inner surface 92 ofthe sliding sleeve 70 to the first surface 104. The body portion 110 mayhave a second side surface 114 extending from the inner surface 92 ofthe sliding sleeve 70 to the second surface 106. The first side surface112 may be disposed at a third angle relative to the longitudinal axis48 of the first transmission shaft 42. The second side surface 114 maybe disposed at a fourth angle relative to the longitudinal axis 48 ofthe first transmission shaft 42. The first side surface 112 and thesecond side surface 114 may be spaced apart from each other and disposedin a non-parallel relationship. The first side surface 112 and thesecond side surface 114 may become progressively farther apart from oneanother along an axial direction along the sleeve tooth 100 towards thetip 102.

The first side surface 112 may have a length, Is.sub.1. The second sidesurface 114 may have a length, Is.sub.2. The length, Is.sub.1, and thelength, Is.sub.2, may be substantially similar. The length, Is.sub.1,and the length, Is.sub.2, may be greater than the first length, I.sub.1,and the second length, I.sub.2, respectively.

The fixed hub 72 is configured to be slidably received within thesliding sleeve 70 which may define the sliding sleeve assembly 84. Thefirst transmission shaft 42 may include a plurality of splined teethdisposed about an outer surface of the first transmission shaft 42. Thefixed hub 72 may engage at least one of the plurality of splined teethof the first transmission shaft 42 via splined teeth disposed about aninner diameter of the fixed hub 72.

The fixed hub 72 may have a plurality of gear teeth 120. The pluralityof gear teeth 120 extend radially outward from a root diameter of thefixed hub 72. The plurality of gear teeth 120 may be configured toengage or mesh with the sleeve spline or plurality of sleeve teeth 96.The fixed hub 72 may define a notch 122 disposed proximate the rootdiameter of the fixed hub 72 and spaced apart from the plurality of gearteeth 120.

The fixed hub 72 may include at least one pre-energizer 130. Thepre-energizer 130 may be configured to engage at least one sleeve tooth100 of the plurality of sleeve teeth 96. The pre-energizer 130 mayinclude a roller, a strut, or a spring disposed about a plunger. Thepre-energizer 130 may be received within a cavity extending radiallyinward from the root diameter of the fixed hub 72. The pre-energizer 130may be retained within the cavity by the internal diameter of thesliding sleeve 70 or the plurality of sleeve teeth 96.

Responsive to movement of the gear selector fork 62, the sliding sleeve70 may be moved towards the desired gear, for example the first gear 44or the second gear 46. The pre-energizer 130 assists in translating thesliding sleeve 70 towards the desired gear during gear synchronizationand engagement.

The blocker ring 74 may be disposed proximate the fixed hub 72. Theblocker ring 74 may have a first end region 140 disposed proximate theengagement ring 78. The blocker ring 74 may have a second end 142 spacedapart from the first end region 140 and a generally cylindrical body 144extending therebetween. The generally cylindrical body 144 may have anouter surface 146 and an inner surface 148. The generally cylindricalbody 144 may be disposed concentrically about the axis 48 of the firsttransmission shaft 42.

The blocker ring 74 may be disposed between the desired gear, theengagement ring 78, and the sliding sleeve assembly 84. In at least oneembodiment, a second blocker ring may be spaced apart from the blockerring 74. The second blocker ring may be disposed on another side of thefixed hub 72 between another desired gear and another engagement ring.

The blocker ring 74 is urged towards the desired gear responsive tomovement of the gear selector fork 62 and the sliding sleeve 70 towardsthe desired gear. As the blocker ring 74 is urged towards the desiredgear, the blocker ring 74 may engage a cone of the engagement ring 78associated with the desired gear. The engagement of the blocker ring 74with the cone of the engagement ring 78 associated with the desired gearmay generate friction resulting in rotation of the blocker ring 74. Thefrictional engagement of the blocker ring 74 with the cone may brake oraccelerate at least one of the sliding sleeve assembly 84 and theengagement ring 78 to approximately match the rotational speed of thedesired gear to complete the transmission shift event.

The main function of the blocker ring 74 is intrinsically related to itsfrictional properties because the blocker ring 74 serves as a frictionalmember to accelerate or brake various components of the transmission 10involved in the transmission shift event. The blocker ring 74 and thecone of the engagement ring 78 may act as a frictional clutch when theyare engaged. Commonly blocker rings are made out of brass, aluminum, orother ferrous alloys. Various surfaces of the metallic blocker ring maybe lined or coated with friction materials such as special papers,fibers, brass, or molybdenum to improve the frictional properties of themetallic blocker ring.

Metallic blocker rings may be manufactured by employing extensivemachining, coating, and heat treatment processes to obtain the desiredfrictional properties. Some thermoplastic materials may have bothmechanical and frictional properties suitable for blocker rings, toenable the use of the thermoplastic material instead of a ferrous alloyand without a separate frictional lining or coating. As such, theblocker ring 74 may be produced by an injection molding process withminimal machining.

The blocker ring 74 comprising a thermoplastic material lighter inweight than a metallic blocker ring. The blocker ring 74 comprising athermoplastic material may have comparable strength, stiffness, andendurance as a metallic blocker ring. The blocker ring 74 comprising athermoplastic material may have additional teeth disposed about theperiphery that may improve shift quality and wear life as compared to ametallic blocker ring.

The thermoplastic material may be a high-performance polymer composite.The high-performance polymer composite may have a tensile strengthwithin a range defined by 200-500 MPa. The high-performance polymercomposite may have 20%-40% carbon fill, such as a PEEK gradehigh-performance polymer composite with carbon fill. The carbon fibersused for the carbon fill may have a length of 0.5 mm to 10 mm anddiameter of 0.05 mm to 1 mm.

In at least one embodiment, the high-performance polymer composite mayinclude glass or aramid fibers, or powdered ceramic fillers from 0-20%in weight. These fillers may improve the mechanical properties and thecoefficient of friction of the blocker ring 74. Exemplary materialproperties of high-performance polymers composites compared to brass areshown in Table 1. Table 1 may define ranges of the material propertiesfor the blocker ring 74.

TABLE 1 Various material properties of high-performance polymerscomposites. Property Units 40% HPCF 30% CF Brass Tensile Strengh (23°C.) MPa 350 260 400 Tensile Modulus GPa 45 25 107 Fatigue Life (120° C.)MPa 170 120 190 10⁷ Cycles Density g/cm³ 1.44 1.40 7.90

The 40% HPCF may be a thermoplastic having a composition including 40%high performance carbon fiber fill. For example, the high performancecarbon fiber may have a length of 3 mm and a diameter of 0.4 mm. The 30%CF may be a thermoplastic having a composition including 30% carbonfiber fill. For example, the high performance carbon fiber may have alength of 1 mm and a diameter of 0.1 mm.

The blocker ring 74 formed of the thermoplastic material may have afirst end region 140, a second end region 142, and a cylindrical body144 extending between the first end region 140 and the second end region142. The first end region 140 may be disposed proximate the engagementring 78. The second end region 142 may be disposed proximate the sleeveassembly 84.

The first end region 140 may be provided with a plurality of moldedclutch teeth 150. The second end region 142 may be provided with amolded spline or plurality of molded grooves 152. The cylindrical body144 may be provided with a molded engagement pad 154.

The plurality of molded clutch teeth 150 may be disposed continuouslyabout a circumference of the first region 140. The plurality of moldedclutch teeth 150 may extend radially outward from a root diameter, Rd,of the blocker ring 74.

Each molded clutch tooth 160 of the plurality of molded clutch teeth 150have an angled end surface 162. The angled end surface 162 may be angledtowards the first end region 140 and angled away from the second endregion 142. The angled end surface 162 may be defined by a third surface164 and a fourth surface 166. The third surface 164 and the fourthsurface 166 may be angled towards the first end region 140 and inclinedwith respect to the second end region 142. The third surface 164 may bedisposed at an angle relative to the longitudinal axis 48 of the firsttransmission shaft 42. The fourth surface 166 may be disposed at anangle relative to the longitudinal axis 48 of the first transmissionshaft 42. The third surface 164 and the fourth surface 164 may define anangle, .theta. Referring to FIGS. 5-6, the third surface 164 and thefourth surface 166 may be disposed at an acute angle, with respect toeach other.

The third surface 164 may have a third length, I.sub.3. The fourthsurface 166 may have a fourth length, I.sub.1. The third length,I.sub.3, and the fourth length, I.sub.1, may be substantially similar toeach other, such that the third surface 164 and the fourth surface 166are symmetric.

The plurality of molded clutch teeth 150 may be configured to engage theplurality of sleeve teeth 96 during a transmission shift event. As shownin FIG. 5A, during a transmission upshift event the third surface 164 ofthe molded clutch tooth 160 engages the second surface 106 of the sleevetooth 100. The engagement between the third surface 164 and the secondsurface 106 defines a first contact area 170. As shown in FIG. 5B,during a transmission down shift event the fourth surface 166 of anadjacent molded clutch tooth engages the first surface 104 of the sleevetooth 100. The engagement between the fourth surface 166 and the firstsurface 104 defines a second contact area 172. The asymmetric design ofthe first surface 104 and the second surface 106 may enable the firstcontact area 170 to be a larger than the second contact area 172.

As shown in FIG. 6, during a transmission upshift event and atransmission downshift event, the symmetric design of the first surface104 and the second surface 106 may enable the first contact area 170 tobe substantially similar to the second contact area 172. The symmetricdesign of the first surface 104 and the second surface 106 and thesymmetric design of the third surface 164 and the fourth surface 166 mayimprove the wear life of the molded clutch tooth 160.

The inner surface 148 of the generally cylindrical body 144 may have aplurality of molded grooves 152 defined by the inner surface 148. Eachmolded groove of the plurality of molded grooves 152 may extend in anaxial direction along the inner surface 148 of the cylindrical body 144.Each molded groove may be disposed substantially parallel to the axis 48of the first transmission shaft 42.

The plurality of molded grooves 152 may be configured as a frictionsurface. Responsive to the sliding sleeve 70 translating the blockerring 74 towards a cone of the engagement ring 78 during a transmissionevent, the plurality of molded grooves 152 engages the cone of theengagement ring 78 responsive to a difference in rotational speedbetween the desired gear and the sleeve assembly 84. The plurality ofmolded grooves 152 engaging the cone of the engagement ring 78 inconjunction with the plurality of molded clutch teeth 150 engaging theplurality of sleeve teeth 96 enables the blocker ring 74 to synchronizethe rotational speeds of the desired gear and the sleeve assembly 84.

The outer surface 146 may have a molded engagement pad 154 extendingradially outwardly from the outer surface 146 of the cylindrical body144. The molded engagement pad 154 may be spaced apart from the firstend region 140. The molded engagement pad 154 may be disposed proximatethe second end region 142. In at least one embodiment, the outerdiameter of the outer surface 146 may be less than the root diameter,Rd, of the first end region 140, such that the first end region 140 andthe cylindrical body 144 are stepped with respect to each other.

The molded engagement pad 154 may be configured to nest within or matewith the notch 122 of the fixed hub 72 of the sliding sleeve assembly84. The molded engagement pad 154 proximately aligns the plurality ofmolded clutch teeth 150 relative to the plurality of sleeve teeth 98 ofthe sleeve spline 96. The molded engagement pad 154 nested within thenotch 122 permits relative movement between the blocker ring 74 and thesliding sleeve assembly 84, including the sliding sleeve 70 and thefixed hub 72. Additionally, the second end 142 of the cylindrical body144 may define a recess 180. The recess 180 may be disposed proximatethe molded engagement pad 154 and configured as an indexing slot. Theindexing slot clocks the blocker ring 74 relative to the sliding sleeveassembly 84.

The blocker ring 74 may be formed by a process comprising injectionmolding. The blocker ring 74 may be formed as a unitary body includingthe molded features such as the molded clutch teeth 150, the pluralityof molded grooves 152, the molded engagement pad 154, and the recess180. The injection molding process may inject the thermoplastic materialinto a mold cavity through at least three injection gates 200.

At least one injection gate 200 may be located proximate the moldedengagement pad 154. In at least one injection molding process, theinjection gates 200 may be equally spaced apart such that the resultingmolded engagement pad 154 are equally spaced apart at 120.degree.intervals. The equal spacing of the injection gates 200 and theresulting molded engagement pads 154 may improve the mechanicalproperties of the blocker ring 74 such as stiffness, strength, etc. andminimize geometric distortions.

The engagement ring 78 may be disposed between the desired gear and theblocker ring 74. The engagement ring 78 has a plurality of gear teeth190 extending radially outward from a root diameter, Re, of theengagement ring 78. The plurality of sleeve teeth 96 may be configuredto engage the plurality of gear teeth 190 during a transmission shiftevent subsequent to or simultaneously with the rotational speed of thedesired gear and the sliding sleeve assembly 84 being approximatelysynchronized.

The engagement ring 78 may have a cone 192 extending axially away from asurface 194 of the engagement ring 78. The cone 192 of the engagementring 78 may extend, tapering towards the fixed hub 72 of the slidingsleeve assembly 84. The frictional engagement between the plurality ofmolded grooves 152 and the cone 192 of the engagement ring 78 defines acone clutch.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the present invention.Rather, the words used in the specification are words of descriptionrather than limitation, and it is understood that various changes may bemade without departing from the spirit and scope of the presentinvention. Additionally, the features of various implementingembodiments may be combined to form further embodiments of the presentinvention.

It should be understood that the mixing and matching of features,elements, methodologies and/or functions between various examples may beexpressly contemplated herein so that one skilled in the art wouldappreciate from the present teachings that features, elements and/orfunctions of one example may be incorporated into another example asappropriate, unless described otherwise above.

What is claimed is:
 1. A transmission gear synchronizer comprising: asliding sleeve having an inner surface defining a sleeve spline; a hubreceived within the sliding sleeve, the hub having a plurality of gearteeth extending radially outward from a root diameter of the hub, theplurality of gear teeth configured to engage the sleeve spline, and anotch disposed proximate the root diameter of the hub and spaced apartfrom the plurality of gear teeth; and a blocker ring comprising athermoplastic material, the blocker ring having a plurality of moldedclutch teeth extending radially outward from a root diameter of theblocker ring, and an inner surface defining a molded spline, theplurality of molded clutch teeth are configured to engage the sleevespline in response to the sliding sleeve engaging the blocker ringduring a transmission shift event.
 2. The transmission gear synchronizerof claim 1 wherein the blocker ring has an outer surface defining amolded engagement pad extending radially outward from the outer surfaceof the blocker ring, the molded engagement pad configured to nest withinthe notch of the hub.
 3. The transmission gear synchronizer of claim 2wherein the notch is configured to substantially align the molded clutchteeth relative to the sleeve spline and permit relative movement betweenthe blocker ring, the hub, and the sliding sleeve when the moldedengagement pad is nested within the notch of the hub.
 4. Thetransmission gear synchronizer of claim 1 wherein the gear synchronizerfurther includes an engagement ring having a cone extending from asurface of the engagement ring towards the hub and gear teeth extendingradially outward from a root diameter of the engagement ring, whereinthe molded spline of the blocker ring is configured to engage the coneduring a transmission shift event.
 5. The transmission gear synchronizerof claim 1 wherein the thermoplastic material comprises ahigh-performance polymer composite.
 6. A transmission gear synchronizercomprising: a sliding sleeve having an inner surface defining aplurality of sleeve teeth extending radially inward from the innersurface of the sliding sleeve towards a transmission shaft, a hub havinga plurality of hub gear teeth extending radially outward from a rootdiameter of the hub, the hub configured to be received within thesliding sleeve; and a blocker ring formed from a thermoplastic materialand disposed adjacent the hub, the blocker ring having (i) a pluralityof molded clutch teeth extending radially outward from a root diameterof the blocker ring, and (ii) an inner surface defining a plurality ofmolded grooves extending axially along the inner surface of the blockerring, wherein each molded groove of the plurality of molded grooves isdisposed substantially parallel to a longitudinal axis of the blockerring.
 7. The transmission gear synchronizer of claim 6 wherein eachsleeve tooth of the plurality of sleeve teeth having a tip, the tipdefined by a first surface disposed at a first angle relative to alongitudinal axis of a transmission shaft and a second surface disposedat a second angle relative to the longitudinal axis of the transmissionshaft.
 8. The transmission gear synchronizer of claim 7 wherein eachmolded clutch tooth of the plurality of molded clutch teeth having anend surface defined by a third surface disposed at a third anglerelative to the longitudinal axis of the transmission shaft and a fourthsurface disposed at a fourth angle relative to the longitudinal axis ofthe transmission shaft, the second surface is configured to engage thethird surface during a transmission upshift event and the first surfaceis configured to engage the fourth surface of an adjacent molded clutchtooth of the blocker ring during a transmission downshift event.
 9. Atransmission gear synchronizer comprising: a sliding sleeve having aninner surface defining a plurality of sleeve teeth extending radiallyinward from the inner surface of the sliding sleeve towards atransmission shaft, each sleeve tooth of the plurality of sleeve teethhaving a tip, the tip defined by a first surface disposed at a firstangle relative to a longitudinal axis of a transmission shaft and asecond surface disposed at a second angle relative to the longitudinalaxis of the transmission shaft; a hub having a plurality of hub gearteeth extending radially outward from a root diameter of the hub, thehub configured to be received within the sliding sleeve; and a blockerring formed from a thermoplastic material and disposed adjacent the hub,the blocker ring having: a plurality of molded clutch teeth extendingradially outward from a root diameter of the blocker ring, each moldedclutch tooth of the plurality of molded clutch teeth having an endsurface defined by a third surface disposed at a third angle relative tothe longitudinal axis of the transmission shaft and a fourth surfacedisposed at a fourth angle relative to the longitudinal axis of thetransmission shaft, the second surface is configured to engage the thirdsurface during a transmission upshift event and the first surface isconfigured to engage the fourth surface of an adjacent molded clutchtooth of the blocker ring during a transmission downshift event, and aninner surface defining a plurality of molded grooves extending axiallyalong the inner surface of the blocker ring, each molded groove of theplurality of molded grooves is disposed substantially parallel to alongitudinal axis of the blocker ring.
 10. The transmission gearsynchronizer of claim 9, further comprising an engagement ring disposedbetween a gear and the blocker ring, the engagement ring having a coneextending axially away from a surface of the engagement ring andtapering towards the hub, wherein the plurality of molded grooves of theblocker ring are configured to frictionally engage the cone during atleast one of the transmission upshift event and the transmissiondownshift event.
 11. The transmission gear synchronizer of claim 9wherein (i) the first surface has a first length and the second surfacehas a second length, the second length greater than the first length,and (ii) wherein the third surface has a third length and the fourthsurface has a fourth length, the third length substantially similar to asecond length of the second surface.
 12. The transmission gearsynchronizer of claim 9 wherein each sleeve tooth of the plurality ofsleeve teeth has a first side surface extending from the inner surfaceto the first surface and a second side surface spaced apart from thefirst side surface, the second side surface extending from the innersurface to the second surface, the first side surface and the secondside surface being progressively farther apart from one another alongthe sleeve tooth towards the tip.
 13. The transmission gear synchronizerof claim 9 wherein the first surface and the second surface are disposedat an acute angle with respect to each other.
 14. The transmission gearsynchronizer of claim 9 wherein the first surface and the second surfaceare disposed at an obtuse angle with respect to each other.
 15. Thetransmission gear synchronizer of claim 9 wherein the engagement of thesecond surface with the third surface defines a first contact area andthe engagement of the first surface with the fourth surface of theadjacent molded clutch tooth of the blocker ring defines a secondcontact area, the first contact area substantially similar to the secondcontact area.
 16. The transmission gear synchronizer of claim 9 whereinthe hub defines a notch and wherein the blocker ring has an outersurface defining a molded engagement pad extending radially outward fromthe outer surface of the blocker ring, the molded engagement padconfigured to nest within the notch of the hub.
 17. The transmissiongear synchronizer of claim 16 wherein the sliding sleeve defines asleeve spline and wherein the notch is configured to substantially alignthe molded clutch teeth relative to the sleeve spline and permitrelative movement between the blocker ring, the hub, and the slidingsleeve when the molded engagement pad is nested within the notch of thehub.
 18. The transmission gear synchronizer of claim 9 wherein thethermoplastic material comprises a high-performance polymer composite.19. The transmission gear synchronizer of claim 9 wherein thethermoplastic material has a tensile strength within a range defined by200-500 MPa.
 20. The transmission gear synchronizer of claim 16 whereinthe blocker ring defines an indexing slot disposed proximate the moldedengagement pad.